In recent years, electronic devices that are easily portable such as tablet terminals and personal digital assistances (PDAs) have been widely used. Such portable electronic devices may become wet with water such as rain during outdoor use, and therefore preferably have waterproof performance. Some of the electronic devices are intended for use in bathrooms or the like, and preferably have higher waterproof performance.
In particular, members that are separate from a housing and exposed to the outside and that are subjected to an external pressure may be warped by the external pressure to cause a gap, which may allow entry of water. Examples of such members include a fingerprint sensor. In tablet terminals with a large area, a significant warp may be caused upon receiving a pressing force, which poses a higher risk of causing a gap.
In order to secure waterproof property around a fingerprint sensor in an electronic device, it has been proposed to affix a packing material to a substrate on which a fingerprint sensor is mounted to fix the packing material to an outer case. It has also been proposed to affix a fingerprint sensor and an outer case to each other using an adhesive.
An electronic device having a structure illustrated in FIG. 19 has been proposed as a waterproof structure for an electronic device. FIG. 19 illustrates an example of a waterproof structure for an electronic device according to the related art. In the waterproof structure according to the related art, a fingerprint sensor 902 is fixed to a substrate 903 provided inside, and an outer case 901 having a projection 911 surrounding the fingerprint sensor 902 is placed so that an O-ring 904 is interposed between the projection 911 and the fingerprint sensor 902. According to the related art, the O-ring 904 provided between the fingerprint sensor 902 and the projection 911 provided inside the housing suppresses entry of water and dust.
Examples of the related art are described in Japanese Laid-open Patent Publication No. 2007-143909, Japanese Laid-open Patent Publication No. 2003-204954, and Japanese Laid-open Patent Publication No. 2010-74439.
In the case where a water stop member is affixed using an adhesive material, however, the adhesive may be peeled because of a reduction in adhesion or a pressing force. Therefore, it is difficult to secure reliability in waterproof performance and dust-proof performance with the related art in which a water stop member is affixed using an adhesive material.
In the mechanism illustrated in FIG. 19, meanwhile, the fingerprint sensor 902 is warped about a support leg 921 by a pressing force applied to the fingerprint sensor 902, which moves an upper end portion 922 in the direction away from the projection 911 of the outer case 901. Then, an upright wall 923 of the fingerprint sensor 902 which interposes the O-ring 904 is deformed inward. This may increase the distance between the upright wall 923 and the projection 911, reduce a force to compress the O-ring 904, and cause a gap around the O-ring 904. In electronic devices in which the outer case 901 has a large area such as tablet terminals, in particular, the outer case 901 is warped significantly. Therefore, the upright wall 923 of the fingerprint sensor 902 is deformed significantly when the fingerprint sensor 902 is pressed, and the pressure applied to the O-ring 904 is highly likely to be reduced. Thus, it is also difficult to secure reliability in waterproof performance and dust-proof performance with the related art illustrated in FIG. 19.
The disclosed technology has been made in view of the foregoing, and therefore has an object to provide an electronic device that achieves seal while securing reliability in waterproof performance and dust-proof performance.